Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[|Fred]

I for my self do not see (so far) any change in the structure in the above picture , compared to the one taken a month ago. May be I'm not looking hard enough ?

 

[AntonL]

However, amount of energy stored in the pool water is impressive, and something occurred to me just now. After the hydrogen explosion there should be an implosion phase - lowering the pressure above water - and that could be enough to start flash boiling.

I like this idea , stated so in https://www.physicsforums.com/showpost.php?p=3199497&postcount=641"

 

[|Fred]

After the hydrogen explosion there should be an implosion phase - lowering the pressure above water - and that could be enough to start flash boiling.

I postulated that the video of unit 3 Blast showed an implosion after the initial "lateral explosion" and before the vertical component. This might not be to far fetched after all

 

[MiceAndMen]

IMHO, Yomiuri Press cannot be taken too seriously. The "Gate Theory" saved by the flood only they reported and I bet that the "Lube & Propane Theory" will remain a Yomiuri exclusive.

However, should it be true then it is really a sad state of affairs that a nuclear power plant can be destroyed by maintenance material. How will nuclear power plants be maintained in the future?

Are the lube barrels that hold potential flammable material nuclear certified? I bet not, just a standard 44 gallon drum.

Are the propane (or is it acetylene that is normally used for welding) and oxygen tanks or cylinders nuclear certified so they can be used in a nuclear power station.

Anton, I agree completely. I was just yanking unlurk's chain. I didn't post the Yomiuri story link; it just happened to pop up at a convenient time.

Propane doesn't seem likely. Acetylene on the other hand... I don't know. It depends on how much there was and where it was being used and stored. We're really getting to the point where we need some mass and energy estimates that might account for what the pictures show us, for both units 3 and 4. Such analyses could help to narrow down the different hypotheses floating around. Unfortunately I don't have the resources to do CFD in my spare time. I doubt anyone here does.

 

[razzz]

I for my self do not see (so far) any change in the structure in the above picture , compared to the one taken a month ago. May be I'm not looking hard enough ?

Yeah, just a different view from ground level instead of overhead. Unit 4 they don't dare breathe on, 2 & 3 are just to 'hot' to work on so only Unit 1 is approachable.

 

[MiceAndMen]

http://www.flickr.com/photos/xtcbz/sets/72157626687253144/

These photos were taken by a person concerned in late April.

I wish to add my thanks for these pictures as well.

 

[Jorge Stolfi]

Forgive me if this is old news that I somehow missed, but these pix are pretty incredible.

The first thing that jumps out at me is that a lot of the upper superstructure of R3 and R4 has vanished since the last time I saw new close-ups.

Indeed, they sem to have been clearing away some of the rubble. For instance, the damaged stairwell enclosure on the service floor of #3 is gone.

The photos of #3 show a concrete-pump-like equipment that seems to be fitted for that task, rather than for water-pumping.

Removing the rubble makes a lot of sense for various reasons: safety of personel below, understanding what happened, clearing the way to the spent-fuel pools, securing loose radioactive material that could be washed down by rain or blown away by the wind, etc..

A few other things that struck me in those photos:

* The crane of #1 is in place at the south end of the service floor and held up the roof slab, although its rails have ceded by a few meters under the weight. Presumably the FHM is parked under it.

* In #3, the explosion pushed part of the south wall on the 4th floor, next to the SW corner,out by ~2 meters. (That explains why I could not fit my POV-ray models to that corner of the building!)

* Also in #3, the crosspiece at the western end of the crane got bent; so that the south longbeam of the crane is resting on the service floor, while the north longbeam sank into it, by a meter or so.

* Also in #3, northwest corner of the equipment pool's wall is missing and seems to have been blasted outwards, contributing to the mess on that corner. Among that is a big pece of equipment, tilted and half sunk into that pool. (The Missing FHM? the Mighty Spanner?)

* There are still lots of spaghetti-like grey rods among that mess at the NW corner of #3. (Rebar? Shouldn't it have rusted by now?)

* In #4, the explosion seems to have traveled down the stairwell at the SW corner, which had a concrete wall around it. There seems to be another stairwell at the NW corner (but withr longer stair sections, and without a concrete wall?), and the explosion apparently went down that way too. (Those two stairwells and the elevator well seem to be the only communication between the service room and the lower floors. The elevator well goes---apparently without any walls---all the way down to the ground floor, where it connects to the entrance "tunnel". Thus the damage to the latter is not entirely surprising. Presumably the truck parked at the tunnel's entrance diverted he blast wave against the walls, thus explaining why the damage is mostly near that end.)

* The artwork on #1's exterior walls is symetric about the NW corner.

 

[AntonL]

Hydrogen diffuses rapidly (Graham's Law), and it's hard to accumulate hydrogen over a long period. Perhaps someone who knows could provide a real radiolysis rate estimate that would refute what I'm arguing, but it appears that hydrogen isn't the cause of this explosion.

I am no expert but just applying knowledge documented by others.

Please see my https://www.physicsforums.com/showpost.php?p=3287847&postcount=6068" and then make your opinion.

Use the links in #6210 to download reference paper - it will be faster

 

[Rive]

http://www.flickr.com/photos/xtcbz/sets/72157626687253144/

These photos were taken by a person concerned in late April.

Many thanks.

This one: "[URL
[/URL] is a turbine building with a blowout panel removed?


Oooops! http://www.tepco.co.jp/en/news/110311/images/110510_1.zip"

 

[rowmag]

Anton, I agree completely. I was just yanking unlurk's chain. I didn't post the Yomiuri story link; it just happened to pop up at a convenient time.

Propane doesn't seem likely. Acetylene on the other hand... I don't know. It depends on how much there was and where it was being used and stored. We're really getting to the point where we need some mass and energy estimates that might account for what the pictures show us, for both units 3 and 4. Such analyses could help to narrow down the different hypotheses floating around. Unfortunately I don't have the resources to do CFD in my spare time. I doubt anyone here does.

One thing about propane is that it is heavier than air, and Unit 4 shows much more damage at the levels below the refueling floor than Units 1 and 3, so that would seem to be a point in favor of TEPCO's new theory. (And they seem to be saying they had propane tanks there, no mention of acetylene. Could the Mickey Mouse ears have been propane tanks stored around the back, with a feed through the wall to the welding area, with that feed line leaking as a result of a the earthquake, an aftershock, or the Unit 3 blast?)

 

[Jorge Stolfi]

Yeah, just a different view from ground level instead of overhead. Unit 4 they don't dare breathe on, 2 & 3 are just to 'hot' to work on so only Unit 1 is approachable.

At the southwest corner of unit #3, on the service floor, there used to be a bit of concrete wall, formerly enclosing the stairwell. It was damaged at the base and leaning to the west. Check this AP/Air Photo Service photo from early march:

http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/povray/blueprint/foto/drone/hcrop/reactor3-Z-3.png

That bit of concrete seems gone now.

 

[Borek]

I like this idea , stated so in https://www.physicsforums.com/showpost.php?p=3199497&postcount=641"

So the credit goes to you :shy: That's not the first time (neither in this thread nor in my life) when I force open doors that someone else found a key to much earlier.

The energy had to come from somewhere else and I can't buy into the idea of it coming from the latent heat of the SFP.

See link below. The energy was there.

Tubs of hot water just don't have a reputation for blowing up like that.
This would be a first.

You don't need a tube, glass is enough to see what may happen. http://www.youtube.com/watch?v=1_OXM4mr_i0&feature=fvsr Or google for Old Faithful eruption.

However this runs counter to theory and practical experience with superheated water. Yes, you can make it hiccup, but you just cannot make it flash into large amounts of water vapor. Problem is, 2000 kJ/kg is needed to vaporize water, and it has to come from somewhere. If we assume generously, that the water in the sfp had managed to superheat to 10 deg C above bp , without its boiling, the water would have a surplus energy content of only about 40 kJ/kg. There would be energy to vaporize only 2% of it.

See cphoenix posts, he tried to estimate amount of energy in the heated water and they were really impressive https://www.physicsforums.com/showpost.php?p=3250188&postcount=3914 - and even if there were enough to vaporize "only" 2% that still means very large volume of steam. That would be on top of initial destruction done by the hydrogen detonation. So the hydrogen blows the walls/roof, then steam erupts, adds to the destruction and sends a mighty puff into the sky.

I postulated that the video of unit 3 Blast showed an implosion after the initial "lateral explosion" and before the vertical component. This might not be to far fetched after all

Yep, vertical component would be mainly water geyser after hydrogen kaboom.

The only thing that I still find doubtful is that it needs a substantial heat gradient between the top and the bottom of the pool, and the water should mix by convection. However, stored fuel must slow down the circulation, so could be the energy was there, just not as much as the original estimate shows.

 

[rowmag]

Oooops! http://www.tepco.co.jp/en/news/110311/images/110510_1.zip"

Yikes, that is not pretty.

 

[BlueCactus]

The Isotopes detected from sampling water of #3 Spent Fuel Pool.

Cs134 :1.4 * 10 ^11 [Bq/m3]
Cs136 :1.6 * 10^9
Cs137 : 1.5 * 10 ^11
I131 : 1.1 * 10^10

Location : Southwest side
Depth : 50cm below the water surface
Height : 6m above the fuel rod
volume: 40 cc

*precise value and underwater footage will soon be released.

 

[jlduh]

High levels of Strontium 89 and 90 found in soil around Daichi reactors:

http://www3.nhk.or.jp/daily/english/09_01.html



Note this also:


To the isotopes specialists: does these levels of strontium tells something about the cores destructions or possible criticalities? What are the most possible ways this strontium went there? By dust and particulates during the explosions? By steam?

Ok, in order to group in one post (this one) all the infos so far about STRONTIUM (which is an important subject i think), i add here (already posted):

-the Tepco measurement analysis of soil

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e7.pdf

- and seawater
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e5.pdf

the analysis of air showed no current traces of strontium (volatile or dust)
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e9.pdf

And also this article: Govt to monitor radioactive strontium levels

http://www3.nhk.or.jp/daily/english/09_28.html

Goshi Hosono made the remark to reporters on Monday, one day after Tokyo Electric Power Company detected high concentrations of strontium-90 in soil samples taken on April 18th inside the plant's compound. The amount is about 130 times higher than the maximum level observed within Fukushima Prefecture after past foreign atmospheric nuclear tests.

[...]

Noting the danger of strontium to human health, he said a detailed investigation is needed, including analysis of past data, to determine how the radioactive substance was scattered.

Once inhaled, radioactive strontium accumulates in bones, like calcium, and could cause cancer.

On April 13th, the science ministry announced that 3.3 to 32 becquerels per kilogram of strontium-90 was detected in soil samples from 3 locations in Namie Town and Iitate Village, 30-kilometers from the Fukushima plant. It also said an extremely small amount of strontium was found in plants taken from Motomiya city, Ono Town and Otama and Nishigo Villages, which are 40 to 80 kilometers from the Fukushima plant. The samples were taken on March 16th and 19th, 5 to 8 days after the accident at the plant.

 

[MadderDoc]

<..>
Is this picture credible or was somebody playing with photoshop? it as linked a few pages back.
http://img34.imageshack.us/img34/6077/aerial201133002011.jpg

Well, it is kind of naive. There's no good reason to believe that the reactor cap in unit 3 has a hue similar to a color fill of the reactor cap in a drawing of a bwr. Without the color clue, the picture has really nothing to indicate that it's the cap there in the equipment pool, it could be anything.

 

[razzz]

Anyone use .docstoc? Can you open this link for this document... http://www.docstoc.com/docs/7254461/Reactor-Pressure-Vessel-Issues-Printable-Version

 

[Concrn&Curius]

1. After seeing those photos of the site, all I can say is that the scale of the damage was just plain shocking.
2. I have a question about unit 3: Has anyone been watching wind directions since the accident? I know I have seen dispersions of the fallout that all indicate a NW trajectory. After seeing those photos, it looks like unit 3 was a cannon aimed in that direction. The Eastern walls are more intact, and the NW corner is just wrecked. That is where the flame "escaped?" as well. Would that all be consistent?

 

[razzz]

1. After seeing those photos of the site, all I can say is that the scale of the damage was just plain shocking.
2. I have a question about unit 3: Has anyone been watching wind directions since the accident? I know I have seen dispersions of the fallout that all indicate a NW trajectory. After seeing those photos, it looks like unit 3 was a cannon aimed in that direction. The Eastern walls are more intact, and the NW corner is just wrecked. That is where the flame "escaped?" as well. Would that all be consistent?

I read the wind direction carrying the explosion from Unit 1 caused most of the fallout/no-go zone since the cloud from Unit 3 explosion was carried by the winds directly offshore. Besides the ongoing uncontrolled releasing of contamination.

 

[AntonL]

Oooops! http://www.tepco.co.jp/en/news/110311/images/110510_1.zip"

What a mess, remote controlled submarines will be needed to clear the rubble to get to the spent fuel.

All I see are roof beam sections, rebar and concrete rubble, what is up or down is difficult to judge, bubbles seem to move horizontally at times,

look at the corrosion on whatever these are (right hand side)
[PLAIN]http://k.min.us/inkut8.JPG

 

[Jorge Stolfi]

Well in order to melt either the Boral metal or the Boraflex plastic, the fuel would have to be not under water. Then it could melt, if the water were gone. But without water it can't go critical.

By the time fuel became partly uncovered and the rods heated up to >700C, the space between the fuel rods would be filled with superheated steam. Also the space above the fuel, up to the top of the SFP, would be filled mostly with hot steam (except for some air flowing down by convection). Would that be enough water to allow for criticality?

The density would be much less than liquid water, but the volume would be much larger than inside a reactor's core. I presume that fast neutrons that escaped upwards or sideways would not be readily absorbed, and so would eventually be slowed down and scattered back to the fuel. Here I am thinking by analogy with light that falls onto a deep cloud deck: since it is scattered but not absorbed by the water droplets, it will all eventually scatter back out, exiting on the same side it entered --- no matter how rarefied the cloud dech is. (That is why large clouds look white on the sunlit side, and black on the other side). In the above scenario, H2 nuclei and neutrons would substitute for water droplets and photons.

 

[|Fred]

At the southwest corner of unit #3.

this is correct the frame is still there but the thin concrete seems gone? or may bi it is the white structure at the bottom of the picture (unlikely though)


New video on Tepco press downloads - this time it's about SFP#3!
=> at last .. we don't see much beside lots of roof structure fallen into the pool

 

[~kujala~]

Also, lubricating oil should not create an explosive mixture with air, unless it is heated to its boiling point, which presumably is >>100 C.

As fas as I have understood the current view of TEPCO is that at the unit 4 there was first an explosion and only afterwards fire. At least this is the impression I have got when reading TEPCO's/government's press releases.

I think one could achieve the best results by taking somehow seriously this new information coming from the press and trying to combine it with the theories presented here and try to see does it lead somewhere.

The general fire point of lubricating oil is probably somewhere betweeen 200 - 300 degrees celsius.

We could also think that this oil is in responsible for the fire but not for the explosion.

Is it possible that the explosion could have immediately heated a small part of the oil over fire point and also ignited it? The result of this would be a couple of fires here and there that would be extinguished by itself?

The explosion itself could be explained by AntonL's theory (radiolysis) or something else.

 

[MiceAndMen]

* The artwork on #1's exterior walls is symetric about the NW corner.

I'm fairly certain the artwork is symmetric on all the RBs with respect to the NW and SE corners.

Oooops! http://www.tepco.co.jp/en/news/110311/images/110510_1.zip"

Oh my.

 

[elektrownik]

oil fire ? but where is ignition source ? reactor was without power source so only hot thing could be fuel...

 

[SteveElbows]

I know I was moaning a lot the other day about people posting images from the live feed and getting hopelessly carried away with ideas about what they are seeing, but now I am going to do the same!

The attached picture was captured from the live feed by me about 10 minutes ago. Whats up with unit 2 building and the large dark rectangle on the west wall?

 

[elektrownik]

I know I was moaning a lot the other day about people posting images from the live feed and getting hopelessly carried away with ideas about what they are seeing, but now I am going to do the same!

The attached picture was captured from the live feed by me about 10 minutes ago. Whats up with unit 2 building and the large dark rectangle on the west wall?

This is big crane under damaged roof, but it is unit 1 not 2

 

[quark42]

Anyone use .docstoc? Can you open this link for this document... http://www.docstoc.com/docs/7254461/Reactor-Pressure-Vessel-Issues-Printable-Version

Here's the link to the PDF at the NRC's site: http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/prv.pdf"

First post here. I've been reading this thread since around the #350th post and I'd like to thank all the contributors. I've learned an incredible amount about nuclear physics and the engineering of nuclear reactors.

Keep up the good work. Back to lurking...

 

[MiceAndMen]

I know I was moaning a lot the other day about people posting images from the live feed and getting hopelessly carried away with ideas about what they are seeing, but now I am going to do the same!

The attached picture was captured from the live feed by me about 10 minutes ago. Whats up with unit 2 building and the large dark rectangle on the west wall?

I think the dark rectangle is the south wall of unit 1. Have a look at this new picture from the set recently posted:
http://www.flickr.com/photos/xtcbz/5705865264/in/set-72157626687253144/

Unit 2 looks fine.

 

[SteveElbows]

This is big crane under damaged roof, but it is unit 1 not 2

Aha yes, thanks, I made a very simple and stupid mistake. Sorry about that!

 

[elektrownik]

About unit 3 from tepco news:

- From 4:18 pm on May 8th to 5:41am on May 10th, we drained the water from
the condenser of the turbine building in Unit 3 as a preparation for the
water injection to the reactor through Feeding Water System.

 

[zapperzero]

* There are still lots of spaghetti-like grey rods among that mess at the NW corner of #3. (Rebar? Shouldn't it have rusted by now?)

Steel wire?

 

[AntonL]

This is big crane under damaged roof, but it is unit 1 not 2

crane? That in my opinion is the high voltage overhead line tower.
[PLAIN]http://k.min.us/inkOf6.JPG

 

[Jorge Stolfi]

Well in order to melt either the Boral metal or the Boraflex plastic, the fuel would have to be not under water. Then it could melt, if the water were gone. But without water it can't go critical.

Would this qualify as a crude nuclear reactor (with steam as neutron reflector/moderator):

EDIT+: Imagine that the water is boiling vigorously, so the steam is heating up as it flows along the hot fuel tubes; but leaves the racks when it is still well below 800 C, so the assembly heads (where no heat is being generated) remain relatively cool and undamaged.

 

[ascot317]

Oooops! http://www.tepco.co.jp/en/news/110311/images/110510_1.zip"

I had feared it would look bad judging by the drone pictures, but this is just terrible.

It's a bit confusing and I yet have figure directions out, but where's the fuel? How sturdy are spent fuel racks normally?